The purpose of the overall project is to provide a better understanding of the means by which free muscle grafts in mammals become structurally and functionally reintegrated with the body of the host. The main focus is upon those processes which occur early during the postoperational course of the transplant. During the coming year the investigation will concentrate upon four main areas. 1) A description of the ultrastructural morphology of free muscle grafts, with special emphasis on the pattern of survival and degeneration in normal, predenervated and Marcaine-treated muscles. 2) Investigation of the pattern of early revascularization in free muscle grafts with the aid of the intravital microscope. 3) Description of the time course and topographical pattern of reinnervation of free muscle grafts. 4) The development of better models to demonstrate and analyze the muscular neurotization of free muscle grafts. BIBLIOGRAPHIC REFERENCES: Gutmann, E., and B. Carlson 1976 Innervation of free muscle grafts in the rat in the absence of mechanical trauma to surrounding muscles or nerves. Life Sci., 19: 649-656. Carlson, B.M. 1976 A quantitative study of muscle fiber survival and regeneration in normal, predenervated and Marcaine-treated free muscle grafts in the rat. Exp. Neurol., 52: 421-432.